Study on the Effect of Sm<sub>2</sub>O<sub>3</sub> Particle on Crystal Grain Size and Inclusion of Low Carbon Steel

Abstract

The second phase particle in steel can refine crystal grain and improve performance of steel products. In the paper, how Sm2O3 particle affecting on inclusion and crystal grain size of steel product was studied by adding Sm2O3 particle into steel. The result shows the Sm2O3 particle will not agglomerate and the content of inclusion in steel will not increase when the particle size is lower than 1.47μm while the content of inclusion will increase obviously when the size is higher than 3.41μm. The Sm2O3 particle can combine with sulfide inclusion and deoxided product, which has the same function as adding rare earth alloy into steel partially. So the Sm2O3 particle can refine the size of crystal grain of cast structure. The degree of crystal grain was reduced from level 2 to level 4-4.5 and the average size of crystal grain was reduced from 180μm to 90-75μm. And it can also reduce the size of crystal grain of rolled structure. The degree was reduced from level 6.5 to level 11 and it will decrease with increasing of adding content of Sm2O3 particle. The best economic and technical norms can be got when the l size of Sm2O3 particle is 1.47μm and the adding content is 0.5% of the content of metal.